Add support for recording/running ref tests

Ref tests use a recording of the terminal protocol and a serialization
of the grid state to check that the parsing and action handling systems
produce the correct result. Ref tests may be recorded by running
alacritty with `--ref-test` and closing the terminal by using the window
"X" button. At that point, the recording is fully written to disk, and a
serialization of important state is recorded. Those files should be
moved to an appropriate folder in the `tests/ref/` tree, and the
`ref_test!` macro invocation should be updated accordingly.

A couple of changes were necessary to make this work:

* Ref tests shouldn't create a pty; the pty was refactored out of the
  `Term` type.
* Repeatable lines/cols were needed; on startup, the terminal is resized
* by default to 80x24 though that may be changed by passing
  `--dimensions w h`.
* Calculating window size based on desired rows/columns and font metrics
  required making load_font callable multiple times.
* Refactor types into library crate so they may be imported in an
  integration test.
* A whole bunch of types needed symmetric serialization and
  deserialization. Mostly this was just adding derives, but the custom
  deserialization of Rgb had to change to a deserialize_with function.

This initially adds one ref test as a sanity check, and more will be
added in subsequent commits. This initial ref tests just starts the
terminal and runs `ll`.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/renderer/mod.rs b/src/renderer/mod.rs
index 333604f6..dfaf6b30 100644
--- a/src/renderer/mod.rs
+++ b/src/renderer/mod.rs
@@ -1100,6 +1100,7 @@ impl From<io::Error> for ShaderCreationError {
 ///
 /// The strategy for filling an atlas looks roughly like this:
 ///
+/// ```ignore
 ///                           (width, height)
 ///   ┌─────┬─────┬─────┬─────┬─────┐
 ///   │ 10  │     │     │     │     │ <- Empty spaces; can be filled while
@@ -1112,6 +1113,7 @@ impl From<io::Error> for ShaderCreationError {
 ///   │     │     │     │           │ <- Row considered full when next glyph doesn't
 ///   └─────┴─────┴─────┴───────────┘    fit in the row.
 /// (0, 0)  x->
+/// ```
 #[derive(Debug)]
 struct Atlas {
     /// Texture id for this atlas